Symmetry typically characterizes the impact of a liquid droplet on a solid surface,where uniform spreading is followed by radial retraction.Breaking this symmetry tra-ditionally relies on engineering surface propertie...Symmetry typically characterizes the impact of a liquid droplet on a solid surface,where uniform spreading is followed by radial retraction.Breaking this symmetry tra-ditionally relies on engineering surface properties.Here,we introduce an alternative approach to achieve asymmetric droplet impact by incorporating a pair of bubbles into the liquid droplet,resulting in the coexistence of spreading and retraction.The asym-metric dynamics originate from the anisotropic capillary effects that can be adjusted by varying the volume fraction of bubbles and the impact velocity.The early onset of retraction enhances upward liquid momentum,facilitating prompt droplet takeoff and significantly reducing both the contact area(up to 50%)and contact time(up to 60%).Thisreductionalsodiminishesheat exchangebetweenthedroplet andthesurface.Our findings pave the way for applications that capitalize on reduced contact times through droplet engineering,eliminating the need for surface modifications.展开更多
基金Research Grants Council of Hong Kong,Grant/Award Number:21213621National Natural Science Foundation of China,Grant/Award Number:52303046City University of Hong Kong,Grant/Award Number:7006097。
文摘Symmetry typically characterizes the impact of a liquid droplet on a solid surface,where uniform spreading is followed by radial retraction.Breaking this symmetry tra-ditionally relies on engineering surface properties.Here,we introduce an alternative approach to achieve asymmetric droplet impact by incorporating a pair of bubbles into the liquid droplet,resulting in the coexistence of spreading and retraction.The asym-metric dynamics originate from the anisotropic capillary effects that can be adjusted by varying the volume fraction of bubbles and the impact velocity.The early onset of retraction enhances upward liquid momentum,facilitating prompt droplet takeoff and significantly reducing both the contact area(up to 50%)and contact time(up to 60%).Thisreductionalsodiminishesheat exchangebetweenthedroplet andthesurface.Our findings pave the way for applications that capitalize on reduced contact times through droplet engineering,eliminating the need for surface modifications.
